Method and apparatus for inoculating and streaking a medium in a plate

ABSTRACT

An apparatus for inoculating and streaking a solid growth culture medium in a plate, the streaking using a streaking applicator having a line of resiliently and flexibly supported spaced apart contact surfaces, the apparatus including:
     (a) an inoculating and streaking station including:
       a plate work position having a notional action line fixed in two dimensions (x,y) in a predetermined position; and   a plate rotation device for rotating a positioned plate to cause streaking;   
       (b) a sensor capable of locating the surface of the medium in a positioned plate to thereby determine for that plate, prior to inoculation and streaking of that plate, the third dimension (z) of the action line;   (c) an inoculating device capable of dispensing inoculum, along the action line, on the surface of the medium in the positioned plate; and   (d) a streaking device capable of moving the streaking applicator such that its line of spaced apart contact surfaces contacts, along the action line, the surface of the medium in the positioned plate, prior to rotation of the positioned plate for streaking.

FIELD OF THE INVENTION

The present invention relates to the inoculation of solid growth culturemedia with a microbiological sample, and the subsequent streaking of theinoculum to produce isolated bacterial colonies, principally fordiagnostic purposes such as medical diagnostic purposes. The presentinvention particularly relates to both a method and an apparatus for usein a microbiological laboratory.

BACKGROUND OF THE INVENTION

The isolation of individual colonies of micro-organisms (and inparticular bacteria) is an important procedure in many microbiologicallaboratories. Traditionally, this isolation of bacteria has beenperformed manually by skilled laboratory technicians who first dispensea microbiological sample onto the surface of a solid growth culturemedium, such as agar in a Petri dish (which will hereafter simply bereferred to as a “medium” in an “agar plate” or simply in a “plate”),followed by the use of a hand-tool to spread the sample across thesurface of the medium (called “streaking”).

The hand-tool typically includes a terminal loop to make multiplestreaks of increasing dilution of the inoculum across the medium. Thestreaks of increasing dilution tend to provide, generally towards thetail of the streaks, a number of single cells that allow for the growthof isolated microbiological colonies after incubation. These isolatedcolonies may then be analysed for colony morphology, and may undergostaining and other procedures which are necessary for determining, forexample, the genus, the species and the strain of the previouslyunidentified organism.

Such inoculation and streaking is highly repetitious and in manypathology diagnostic microbiology laboratories is usually conducted invery high volumes, such as in volumes as high as 1,000 to 15,000 platesper day. It is tedious and laborious work that therefore is prone toerror and inaccuracies. It is quite obviously work that would lenditself to either partial or full automation.

The literature is replete with suggestions for how best to automatethese laboratory functions, yet very few of these suggestions have everactually found success in a commercial laboratory environment. Ittherefore appears that the successful enablement of suitable laboratoryapparatus has to date, for most, proved elusive.

A sample of patent documents that, since the early 1970's, havesuggested different apparatus for automating the inoculation andstreaking of solid growth media are U.S. Pat. No. 3,778,351 (R. J.Rosov) titled “Automatic Bacterial Specimen Streaker”, U.S. Pat. No.3,844,896 (A. N. Sharpe) titled “Apparatus for PerformingBacteriological Tests Automatically”, U.S. Pat. No. 3,850,754 (J. R.Wilkins et al) titled “Automatic Inoculation Device”, U.S. Pat. No.3,935,075 (R. C. Perry et al) titled “Automatic Bacterial SpecimenStreaker and Method for Using Same”, U.S. Pat. No. 4,144,135 (P. J. L.Sequeira) titled “Spreader Device and Method of Spreading Inoculant”,U.S. Pat. No. 4,287,301 (T. W. Astle) titled “Method and Apparatus forStreaking Agar”, and U.S. Pat. No. 4,613,573 (K. Shibayama et al) titled“Automatic Bacterial Colony Transfer Apparatus”. To the best of theapplicant's knowledge, none of these suggestions have been successfullyenabled, and thus suitable automation is still not available for suchinoculating and streaking.

Three further, more recent, suggestions from the prior art require somediscussion. They are the suggestions made by Vista Laboratories Ltd inU.S. Pat. No. 4,981,802 (C. Wylie et al) titled “Method and Apparatusfor Streaking a Culture Medium”, the Canadian Space Agency in U.S. Pat.No. 6,617,146 (F. Naccarato et al) titled “Method and Apparatus forAutomatically Inoculating Culture Media With Bacterial Specimens FromSpecimen Containers”, and Medvet Science Pty Ltd in international patentpublication WO2005/071055 titled “Microbial Streaking Device” (licensedto the present applicant).

The Wylie patent describes an apparatus that only partially automatesthe inoculation and streaking process, in that it provides an apparatusfor streaking a solid growth culture medium that has been manuallyinoculated by a laboratory technician, with the laboratory technicianmanually identifying upon the side of a plate the physical location ofthe inoculum (which identifying mark is later sensed by the streakingmechanism to determine where to commence streaking from). Furthermore,the streaking mechanism suggested for use by Wylie is a complex multiplehead mechanism that relies on multiple passes across the medium by asingle-point tool so as to provide a sinuous streaking path. The Wylieapparatus is thus reasonably slow and provides only a partial responseto the automation challenge.

The Naccarato patent describes an automated process for single-pointinoculation of a solid growth culture medium (at any location on thesurface) from one of a possible variety of different forms of specimencontainer, followed by the subsequent use of a traditional, single-pointstreaking tool again following a convoluted path across the surface ofthe medium to thereby spread the inoculum. So that the streaking toolknows where the inoculum will be on the surface, the Naccarato apparatusdescribes the use of a reasonably complex device for recording theprecise location of the inoculum, once the inoculum is placed on thesurface, for use in subsequently guiding the streaking tool to thatrecorded location. These intermediate recordal and guiding steps,intermediate in the sense that they occur between inoculation andstreaking, appear to introduce an undue risk of error and alsounnecessary delays in the overall process.

The Medvet Science publication seeks to improve the automation processby the use of a new form of streaking tool, which tool includes a lineof spaced apart contact surfaces (for contact with the surface of solidgrowth culture media), the contact surfaces being resiliently flexiblysupported by a common support member. This streaking tool permitsgreater spread of a larger volume of the inoculum across the surface ofthe medium with a single streaking pass, as well as larger areas of moregradually increasing dilution of the sample. The inoculating andstreaking apparatus described in the Medvet Science publication suggeststhe use of a pressure sensor to determine when the contact surfaces ofthe streaking tool have contacted the surface of the medium, withoutdescribing how the streaking tool knows the location of the inoculum onthe surface (in terms of both two dimensional and three dimensionalspace).

It is an aim of the present invention to provide an automated apparatusfor the inoculation and streaking of a microbiological sample on thesurface of a solid growth culture medium, together with a method for theinoculation and streaking of a microbiological sample on the surface ofa solid growth culture medium.

Before turning to a summary of the present invention, it must beappreciated that the above description of the prior art has beenprovided merely as background to explain the context of the invention.It is not to be taken as an admission that any of the material referredto was published or known, or was a part of the common general knowledgein Australia or elsewhere.

It is also useful to provide an explanation of some of the terms thatwill be used to define the spatial relationship of the apparatus andvarious parts thereof. In this respect, spatial references throughoutthis specification will generally be based upon a plate ultimately beinginoculated and streaked in an upright orientation, with the surface ofthe medium in the plate being generally flat and horizontal. With thisenvironment as the basis, the apparatus and some parts thereof may thenbe defined with reference to the “horizontal”, allowing furtherreferences to “upper” or “upwardly” and “lower” or “downwardly”, andalso to the “vertical”. In this respect, the traditional geometricspatial reference to x,y and z dimensions, and then to the x direction(or axis), the y direction (or axis) and the z direction (or axis), willalso be adopted, with the x and y directions lying generallyhorizontally and the z direction lying generally vertically.

Finally, some aspects of the present invention that may ultimately beclaimed in isolation (and not in an in-use environment), may nonethelessbe difficult to describe and understand in isolation. Thus, some of thefollowing description does describe the invention and its embodiments insuch an in-use environment (for example, with a plate carrying mediumwithin the apparatus for the purposes of inoculation and streaking). Ofcourse, it must be appreciated that the use of such description, and theuse of the abovementioned spatial relationships, to define the presentinvention, is not to be seen as a limitation and certainly is not to beseen as a limitation only to the in-use environment, unless that isclearly stated to be the intention.

SUMMARY OF THE INVENTION

The present invention provides an apparatus for inoculating andstreaking a solid growth culture medium in a plate, the streaking usinga streaking applicator having a line of resiliently and flexiblysupported spaced apart contact surfaces, the apparatus including:

-   (a) an inoculating and streaking station including:    -   a plate work position having a notional action line fixed in two        dimensions (x,y) in a predetermined position; and    -   a plate rotation device for rotating a positioned plate to cause        streaking;-   (b) a sensor capable of locating the surface of the medium in a    positioned plate to thereby determine for that plate, prior to    inoculation and streaking of that plate, the third dimension (z) of    the action line;-   (c) an inoculating device capable of dispensing inoculum, along the    action line, on the surface of the medium in the positioned plate;    and-   (d) a streaking device capable of moving the streaking applicator    such that its line of spaced apart contact surfaces contacts, along    the action line, the surface of the medium in the positioned plate,    prior to rotation of the positioned plate for streaking.

The inoculating and streaking station (often hereafter simply referredto as the “station”) is the location, defined by a structure, within theapparatus where the main functions of the apparatus occur, thatstructure being generally centered around the plate work position. Inone form, the plate work position is provided by the physical locationin the apparatus of the sensor, the sensor ideally being rigidly mountedto a main frame. In this form, a platform for supporting a plate ispreferably able to be moved into and out of the plate work position(translated along, for example, the y axis) from a plate loadingposition, such that the plate supported in the platform becomespositioned in the plate work position operatively adjacent (whichideally is underneath) the sensor with its medium surface open upwardly.

The platform preferably includes a plate centering mechanism forensuring the proper (and consistent) central positioning of a plate uponthe platform, the plate centering mechanism preferably being driven by asuitably arranged cam device and including a plate clamping function.The platform also preferably provides at least one locating datum pointor surface, the use for which will become evident below when describingthe functioning of the sensor.

In this form, the plate rotation device is preferably also provided inassociation with the platform, the rotation device including a home flagwhich allows for the return of a rotated plate to a starting position.The provision of such a home flag is useful for operation of the methodand apparatus of the present invention with “half” plates as opposed to“full” plates, a description of which will be provided below.

The inoculating and streaking station is of course also able to beaccessed by both the inoculating device and the streaking device (inaddition to the sensor, as described above) such that a plate positionedin the plate work position (throughout this specification referred to asa “positioned plate” and typically being a de-lidded plate or, in otherwords, a plate bottom) can be operatively accessed by each of thesensor, the inoculating device and the streaking device. With regard tothe reference to “operative” access, it will be appreciated that the useof this word merely indicates that access by an element is to be suchthat that element is then able to perform its required function.

As mentioned above, the plate work position includes a notional actionline fixed in two dimensions (x,y) in a predetermined position. Thisaction line is herein referred to as being a “notional” action linegiven that it will not be a visible action line and also will not have adetermined position in three dimensional space until the height of thesurface of medium in a positioned plate is determined. Nonetheless, itis this action line that is operatively accessed by both the inoculatingdevice, for dispensing of the inoculum, and the streaking device, forstreaking of the inoculum, during operation of the apparatus.

In a preferred form, the predetermined (x,y) position of the action linewill, with reference to a positioned plate, be located such that theaction line will be a radial line for a circular plate. In this form,during streaking, the positioned plate can be rotated about its centreby the plate rotation device of the station such that the line ofcontact surfaces of the streaking applicator moves about the centre ofthe positioned plate across the surface of the medium. For a half-plate,two such radial lines would normally be determined, one for each half ofthe plate, such that two inoculum deposits can be made and two streakingoperations conducted.

It will be appreciated that the height of medium, such as agar, within aplate will fluctuate depending upon many factors. For example, not onlydo different plate and solid growth culture medium suppliers invariablyproduce agar plates, for example, with a wide variety of surface heightsfrom one supplier to the next, but even the same suppliers tend tosupply their own plates with varying heights of media. Also, differentcompositions and ages of media used for this purpose tend also toproduce plates with different media surface heights.

Therefore, and due to such fluctuations in height, it is generally notpossible for an apparatus such as that of the present invention to relyupon the height of the surface of media in all plates to be the same(and thus be the same distance above, in one form of the invention, thelocating datum surface of the platform mentioned above).

It is therefore not feasible for an inoculating device of such anautomated apparatus to rely on being able to place inoculum upon thesurface of media at the same location in three dimensional space forevery plate to be processed thereby, and significant difficulties andcomplexities are introduced in an apparatus that does. Of course, thereare also potential difficulties and complexities for the streakingdevice of such an automated apparatus in trying to place the contactsurfaces of a streaking tool upon the surface (so as to spread theinoculum rather than to gouge the surface) of media at the same locationfor every plate in three dimensional space.

In relation to the inoculating device, it will be appreciated that theincorrect location of a dispensing tip on the inoculation device in thez dimension (height) will give rise to the inoculum being dispensed fromtoo high (and thus not dispensing as required), or there being contactwith the surface such that the tip gouges the surface of the medium. Inrelation to the streaking device, incorrect location of the contactsurfaces in the z dimension (height) will give rise to there eitherbeing no contact with the inoculum whatsoever, or there being too muchcontact such that the streaking tool gouges tracks in the surface of themedium.

Accordingly, and as mentioned above, the apparatus of the presentinvention includes a sensor capable of locating the surface of themedium in a positioned plate to thereby determine for that plate, priorto inoculation and streaking of that plate, the third dimension (z) ofthe action line. The sensor is then able to determine the location ofthe surface of the medium in each positioned plate separately, after theplate is positioned but before inoculation, in order to cope with thepossibility of surface height fluctuations and avoid the difficultiesmentioned above.

In a preferred form, the sensor is able to sense the medium surface fora positioned plate and measure the distance to the medium surface. Then,the measured distance is referenced to a fixed datum level to determinea surface positional reference relative to that datum level in onedimension (z) for the surface in the positioned plate. In this manner,it will be appreciated that the surface can thus be located in at leastthe z dimension by virtue of the determination of this surfacepositional reference. This effectively determines the height of themedium in the plate, at least with reference to that datum level.

In this respect, the datum level is preferably a surface that forms apart of the plate platform upon which the plate is clamped andsupported. Therefore, in this form, the determination of the surfacepositional reference effectively determines the surface height of themedium with reference to the plate platform upon which it rests.

This surface positional reference can then be used, together with thenotional action line to determine a line in three dimensions (x,y,z)that is representative of a line across the surface in the positionedplate.

In a preferred form, the sensor and its mode of operation may includethe additional step of setting an upper detection limit and a lowerdetection limit, in some forms with the upper detection limit above thedatum level and the lower detection limit below the datum level, todefine a detection range between the upper and lower limits. A detectionrange can provide a calibration opportunity and allows theidentification of, for example, multiple calibration sub-ranges to beapplied within the detection range.

For example, in some forms, it may not be necessary or desirable for themethod to be able to determine if a plate positioned in the plate workposition still includes its lid thereon, or perhaps has been placed inthe plate work position upside down. Thus, by adopting a narrowdetection range, where the upper limit is only just above where thesurface of the medium is expected to be, and the lower limit is onlyjust below where the surface of the medium is expected to be, the sensorwill not function if the detectable height of the plate in the platework position is outside this narrow range, due to the sensor detectingeither the surface of the plate lid or the surface of the plate bottom.

Conversely, there may be situations where it is desirable to provide analarm, for example, if a lidded or inverted plate is placed in the platework position. If a suitably broad enough detection range has been set,the sensor will thus sense the presence of the lid wall or the bottomwall, and will measure the distance to that surface rather than to thesurface of the medium in the plate. Thus, by the provision of a suitablybroad detection range with calibration sub-ranges for alarm conditions(lidded plate or inverted plate, for example) and for non-alarmconditions (de-lidded upright plate), the calibration sub-ranges cancause the identification (by virtue of the determination of the surfacepositional reference and its presence in one of the alarm calibrationsub-ranges) of an alarm condition as well as allow for the properfunctioning of the method.

The notional three dimensional action line that is represented by a lineacross the surface of the medium in the positioned plate (located by thesensor in the manner just described), will be specific to the medium inthat positioned plate only, and may be (and is actually likely to be) adifferent three dimensional action line compared to the surface of thenext plate processed in the plate work position.

Finally with reference to the sensor, reference is made to the presentapplicant's international patent application filed on 11 Jan. 2008titled “Method and Apparatus for Locating the Surface of Solid GrowthCulture Media in a Plate”, claiming priority from Australian provisionalpatent application 2007900147, the full content of which is herebyincorporated by reference, where the sensor in various forms is morefully described. From this co-pending application, it will also beappreciated that the sensor of the apparatus of the present inventionmay play additional roles in the operation of the apparatus, such asbeing able to identify an incorrectly orientated plate in the plate workposition, or an empty plate work position (at a time in the operationwhen there should be a positioned plate), or a plate that has not yetbeen de-lidded (when de-lidding should already have occurred)

Having then utilized the sensor to determine the proper position of theaction line for media in a given positioned plate in three dimensionalspace, the apparatus of the present invention is then able to inoculatealong (either partly or completely along) that action line, on thesurface of the medium in the positioned plate, and then move thestreaking applicator such that its line of spaced apart contact surfacescontacts, again along that action line, at least the inoculum (andpreferably also the surface of the medium itself) on the surface of themedium in the positioned plate, with a predetermined contact pressurethat is suitable for the particular streaking tool being used and alsofor the composition of the inoculum and of the particular solid growthmedium being used, such that the inoculum is spread as required and suchthat the streaking tool does not undesirably gouge the surface of themedium.

In this respect, and having stated that the line of contact surfaces ofthe streaking applicator is to be located “along the action line”, itmust be appreciated that strict geometric compliance with this languageis not necessary. In particular, it will be appreciated that the line ofcontact surfaces of the streaking applicator may be positioned so thatthey contact the inoculum (and/or the surface) closely adjacent theaction line, such that the subsequent rotation of the plate causes thestreaking applicator to move through, and thereby spread, the inoculum.It is thus envisaged that the line of spaced apart contact surfaces willcontact the surface either along the action line or closely behind theaction line. The reference to “along the action line” throughout thisspecification, with respect to the streaking applicator, is thus to beunderstood to include this scenario.

The inoculating device of the apparatus of the present invention maythus be any device that is able to obtain and hold a biological sample,generally in a liquid form, and transfer that sample to the surface of amedium in a positioned plate. In one form, the inoculating device willinclude a reasonably typical pipette device mounted to a robot system soas to be movable in the z direction and at least one of the x,ydirections (using the directional terminology adopted above). Thepipette device preferably includes a disposable dispensing tipreleasably secured to a pipette body, secured in a manner that permitseasy disposal of the tip once inoculation has been affected.

The inoculating device is preferably programmable for various inoculumvolumes, and includes a positional height (z direction) referencingsystem capable of determining in three dimensional space the height ofthe location of the dispensing tip relative to the locating datumsurface of the platform mentioned above, and of course relative to thenotional action line mentioned above.

The inoculating device may additionally include means for separatelyimaging the dispensing tip during various of the abovementioned range ofactions, so as to be able to (for example) visually or electronicallymonitor for the presence of a tip prior to sampling. In this respect, inone form of the present invention, this imaging means may additionallyprovide the positional height (z direction) referencing system mentionedabove.

The pipette robot system of the inoculating device is preferably able tomove the pipette device to access the dispensing tip supply, abiological sample station, the plate work position in the inoculatingand streaking station, and also a tip waste disposal chute, whilst alsoincluding suitable tip securing means that allows for a dispensing tipto be secured, used to obtain and hold sample, dispense sample, and thendispose of the used tip. It will thus be appreciated that the pipetterobot system of the inoculating device will move the pipette throughthis entire range of actions for each of the plates being processed bythe apparatus of the present invention.

Further, the streaking device mentioned above is preferably a separatedevice to the inoculating device, and is thus preferably provided by itsown robot system that includes an applicator handling head suitable toobtain (from a supply cartridge) and hold a streaking applicator, andthen transfer that applicator to the plate work position and adjacent apositioned plate (generally all in the x,y plane). The applicatorhandling head then must be able to move the applicator in the zdirection to locate the line of contact surfaces of the applicator alongthe notional action line (and thus upon/within the inoculum on thesurface of the medium in the position plate) as mentioned above.

Streaking applicators preferred for use with the above describedautomated streaking apparatus are the streaking applicators generallydescribed in the abovementioned international patent publicationWO2005/071055 (Medvet Science Pty Ltd) titled “Microbial StreakingDevice” (licensed to the present applicant), the full content of whichis herein incorporated by reference. These streaking applicators can besaid to have a generally flat rectangular form, albeit with two majorinclined portions that together form a very shallow inverted v-shapedbody. An upper portion of the body provides a mounting portion and alower portion of the body provides the line of spaced apart contactsurfaces and a resilient and flexible support member.

With this in mind, the applicator handling head of the streaking robotsystem preferably includes an openable clamping member that is able tograsp and clamp the mounting portion of the applicators mentioned above,the applicators being provided in a supply cartridge of the typegenerally described in the present applicant's international patentapplication filed on 11 Jan. 2008 titled “A Streaking ApplicatorCartridge and a System for Connecting Same to a Streaking Apparatus”,claiming priority from Australian provisional patent application2007900144, the full content of which is hereby incorporated byreference.

The openable clamping member of the streaking robot system preferablyincludes a release catch which is able to interact with a fixed ejectpin located near an applicator disposal chute, such that engagement ofthe pin with the latch causes the clamping member to release theapplicator and allow it to fall into the applicator disposal chute.

The present invention thus additionally provides a method forinoculating and streaking a solid growth culture medium in a plate, thestreaking using a streaking applicator having a line of resiliently andflexibly supported spaced apart contact surfaces, the method includingthe steps of:

-   (a) placing a plate in a plate work position in an inoculating and    streaking station, the plate work position having a notional action    line fixed in two dimensions (x,y) in a predetermined position;-   (b) locating the surface of the medium in the positioned plate to    thereby determine for that plate, prior to inoculation and streaking    of that plate, the third dimension (z) of the action line;-   (c) dispensing inoculum along the action line on the surface of the    medium in the positioned plate;-   (d) moving the streaking applicator such that its line of spaced    apart contact surfaces contacts, along the action line, the surface    of the medium in the positioned plate; and-   (e) rotating the positioned plate in the plate work position for    streaking.

In a preferred form of the present invention, the apparatus and methodincludes an ability to handle plates in their normal laboratoryconfiguration, which traditionally sees the plates stored beforeinoculation and streaking (hereafter referred to as “processing”), andalso after processing, in an inverted orientation. By way ofexplanation, it is usual for solid growth culture medium plates to havea lid and a bottom and be stored upside-down such that their lids arefacing downwardly and their bottoms (containing the agar) are storeduppermost. This is done to prevent any condensation that may form insidethe lid from falling onto the medium surface, which would occur if theplates were not stored in an inverted orientation, thereby damaging theintegrity of the medium and (after treatment) the microbiologicalinoculum.

Therefore, the apparatus of the present invention preferablyadditionally includes a plate supply capable of storing unprocessedplates (hereafter referred to as a “raw plate”) in an invertedorientation, together with a plate transfer feed mechanism that is ableto obtain an inverted raw plate from the plate supply, orientate the rawplate such that its bottom is lowermost and its lid is removed, andtransfer the orientated and de-lidded raw plate bottom to the plate workposition in the station. In one form of the present invention, the platesupply of the apparatus is formed by a plurality of removable cassettes,each cassette able to hold and then feed multiple raw plates to theplate transfer mechanism.

The plate transfer feed mechanism preferably includes an orientationmechanism, the orientation mechanism ideally providing for orientationof at least the bottom of the raw plate about a generally horizontalaxis, together with de-lidding, before the de-lidded plate bottom istransferred into the plate work position. The orientation mechanism ispreferably provided by a pair of opposed jaws, both of which are ideallyprovided by a retractable, vacuum-actuated gripping device, and one ofwhich includes a pair of elongate prongs. When an inverted raw plate isgripped between the jaws, a held position is formed that defines anotional tube above and below the plate.

Preferably, the opposed jaws are mounted such that at least the bottomof the held plate can be rotated about an axis in one of the x or ydirections such that the raw plate bottom can be orientated by 180degrees about that axis to bring the raw plate bottom into its normal,upright orientation (referred to as its worked orientation). In thisform, the raw plate bottom preferably rotates about a generallyhorizontal axis that intersects the notional tube.

Holding the raw plate bottom in this upright or worked orientation, theorientation mechanism is then preferably able to move to be located overthe platform mentioned above, following which the upright and held rawplate bottom may be lowered onto the platform to be centralized andclamped thereby. In one form, all of these motions will occur in asingle continuous movement, such that the raw plate bottom is slightlyraised off the lid from its original orientation (with the lid beingretained in its original orientation), and is then orientated into theworked orientation and lowered onto the platform in one motion. The rawplate bottom can then be left centralized and clamped upon the platformready to be moved into the plate work position, also as mentioned above.

As will be appreciated, the reverse operation then moves the processedplate bottom out of the work plate position, where the lid can bere-applied by again rotating the plate bottom (again, preferably in asmooth continuous motion) into its original inverted orientation.

The orientation mechanism is more fully described in the presentapplicant's international patent application filed on 11 Jan. 2008titled “Method and Apparatus for Orientating a Solid Growth CultureMedium Plate”, claiming priority from Australian provisional patentapplication 20072007900145, the full content of which is herebyincorporated by reference.

The apparatus of the present invention preferably further includes aplate store capable of storing inoculated and streaked (processed)plates, again in an inverted orientation, together with a plate transferstore mechanism that is able to retrieve a processed plate bottom fromthe plate work position, re-orientate and re-lid the processed platebottom, and transfer the processed plate to the plate store. In oneform, the plate store is also formed by a plurality of removablecassettes, each cassette able to receive multiple processed plates fromthe plate transfer store mechanism and then store multiple processedplates.

With regard to the plate transfer store mechanism, it will beappreciated that the orientation mechanism referred to above, as a partof the plate transfer feed mechanism, will preferably additionally playthe roles of retrieving the processed plate bottom from the plate workposition, and re-orientating and re-lidding the processed plate bottom,these steps simply being the reverse of the steps described above forthe orientation mechanism transferring the raw plate into the plate workposition.

Therefore, the present invention also provides an apparatus forinoculating and streaking a solid growth culture medium in a plate, thestreaking using a streaking applicator having a line of resiliently andflexibly supported spaced apart contact surfaces, the apparatusincluding:

-   (a) a plate supply capable of storing raw plates in an inverted    orientation;-   (b) a plate transfer feed mechanism capable of obtaining an inverted    raw plate from the plate supply, orientating the raw plate such that    its bottom is lowermost and its lid is removed, and transferring the    orientated and de-lidded raw plate bottom to the plate work position    in an inoculating and streaking station;-   (c) the inoculating and streaking station including:    -   the plate work position, having a notional action line fixed in        two dimensions (x,y) in a predetermined position; and    -   a plate rotation device for rotating a positioned plate to cause        streaking;-   (d) a sensor capable of locating the surface of the medium in a    positioned plate to thereby determine for that plate, prior to    inoculation and streaking of that plate, the third dimension (z) of    the action line;-   (e) an inoculating device capable of dispensing inoculum, along the    action line, on the surface of the medium in the positioned plate;-   (f) a streaking device capable of moving the streaking applicator    such that its line of spaced apart contact surfaces contacts, along    the action line, the surface of the medium in the positioned plate,    prior to rotation of the positioned plate for streaking;-   (g) a plate store capable of storing processed plates in an inverted    orientation; and-   (h) a plate transfer store mechanism capable of retrieving a    processed plate bottom from the plate work position, re-orientating    the processed plate bottom to its inverted orientation with its lid    on, and transferring the processed plate to the plate store.

Additionally, the present invention also provides a method forinoculating and streaking a solid growth culture medium in a plate, thestreaking using a streaking applicator having a line of resiliently andflexibly supported spaced apart contact surfaces, the method includingthe steps of:

-   (a) storing raw plates in an inverted orientation in a plate supply;-   (b) obtaining an inverted raw plate from the plate supply,    orientating the raw plate such that its bottom is lowermost and its    lid is removed, and transferring the orientated and de-lidded raw    plate bottom to a plate work position in an inoculating and    streaking station, the plate work position having a notional action    line fixed in two dimensions (x,y) in a predetermined position;-   (c) locating the surface of the medium in the positioned plate to    thereby determine for that plate, prior to inoculation and streaking    of that plate, the third dimension (z) of the action line;-   (d) dispensing inoculum along the action line on the surface of the    medium in the positioned plate;-   (e) moving the streaking applicator such that its line of spaced    apart contact surfaces contacts, along the action line, the surface    of the medium in the positioned plate;-   (f) rotating the positioned plate in the plate work position for    streaking; and-   (g) retrieving the processed plate bottom from the plate work    position, re-orientating the processed plate bottom to its inverted    orientation with its lid on, and transferring the processed plate to    a plate store.

It will also be appreciated that the abovementioned method and apparatusmay be advantageously modified to also deal with “half-plates”(sometimes referred to as “bi-plates”). A half-plate is similar to theplates described above, but includes a physical barrier across thecentre of the plate, such as an upstanding wall, that thus divides acircular plate into two semi-circular portions. Half-plates can be usedin a manner such the two halves contain the same composition of solidgrowth culture medium, to be inoculated with the same or different typesof samples, or such that the two halves contain different types of solidgrowth culture medium, again to be inoculated with the same or differenttypes of samples (perhaps for comparative or experimental purposes). Insome situations though, the use of half-plates will simply be to savespace or time.

Where a half-plate is used in the method and apparatus of the presentinvention, it will be appreciated that various operations will beduplicated and some will be modified. For example, to use both halves ofthe half-plate in a situation where the same sample (from the samedispensing tip and using the same streaking applicator) is beinginoculated onto both halves of a plate containing the same type ofmedium, the inoculation will occur twice and the streaking will occurtwice (each time for only half a rotation of the plate, not a fullrotation).

Thus, the plate would first be rotated a full turn to permit the sensor(mentioned above) to identify and locate the upstanding wall and thenreturn the plate to a start position relative to a predetermined (in twodimensions only) notional action line. The first half would have itssurface sensed to locate the action line in three dimensions, for it tothen be inoculated along its action line. The plate would then berotated to a second start position relative to another predetermined (intwo dimensions only) notional action line.

The second half would then have its surface sensed to locate its actionline in three dimensions, for it to then be inoculated along its actionline, and then be streaked.

Turning now to a description of the supply of the microbiological sampleto the apparatus and method of the present invention, the supply systempreferably includes a plurality of sample containers (such as sampletubes) supported in multiple racks on a sample deck (the sample deckbeing accessible by an operator for sample rack input and removal). Thesystem also preferably includes a two axis sample handling andtransportation robot system that is able to manipulate the sample rackssuch that they are operatively accessible to the inoculation device. Interms of the samples themselves, they are likely to be in a liquid orsemi-liquid form and might be: a biological fluid, such as blood, urine,plasma and cerebrospinal fluid; a liquid microbial culture; biologicalextracts; or environmental samples, such as water samples or soil washsamples.

Before turning to a detailed description of a preferred embodiment ofthe method and apparatus of the present invention, it will beappreciated by a skilled addressee that it will also be desirable toinclude within the apparatus a suitable form of barcode applicator andappropriate barcode readers. In a preferred form, barcode labels willhave been applied (either manually or automatically) to each samplecontainer to properly identify and record the presence and movement ofeach sample. Also, a barcode applicator will ideally be incorporatedinto the plate transfer store mechanism such that a suitable barcodelabel can be printed and applied to a processed plate as it is removedfrom the plate work position, in order to match a processed plate withthe sample applied thereto and then to properly identify and record thatprocessed plate.

BRIEF DESCRIPTION OF THE DRAWINGS

Having briefly described the general concepts involved with the presentinvention, a preferred embodiment will now be described that is inaccordance with the present invention. However, it is to be understoodthat the following description is not to limit the generality of theabove description.

In the drawings:

FIG. 1 is a perspective view from the front of an automated streakingapparatus according to a preferred embodiment of the present invention;

FIG. 2 is perspective view from the rear of the apparatus of FIG. 1;

FIGS. 3 a and 3 b are perspective partial views of preferred forms ofplate supply and plate store for the apparatus of FIG. 1;

FIGS. 4 a and 4 b are perspective partial views of preferred forms ofpipette tip and sample supply systems for use with an inoculating devicefor the apparatus of FIG. 1;

FIG. 5 is a perspective view of a preferred form of streaking deviceobtaining a streaking applicator for use with the apparatus of FIG. 1;

FIGS. 6 a and 6 b are perspective partial views of a preferred form oforientation device for use with the apparatus of FIG. 1; and

FIGS. 7 a and 7 b are perspective partial views of a preferredconfiguration of plate work position during inoculation and streaking bythe apparatus of FIG. 1.

DESCRIPTION OF A PREFERRED EMBODIMENT

A preferred embodiment of the present invention will now be described inrelation to the apparatus as illustrated (from the front and the rear)in FIGS. 1 and 2. These figures show unnecessary detail, and so willonly be described to a depth of detail necessary to fully describe theinvention as outlined above.

Further, the subsequent illustrations of FIGS. 3 to 7 each showdifferent parts of the apparatus of FIGS. 1 and 2, and each will againwill be described in sufficient detail to fully describe the inventionas outlined above. In this respect, reference is again made to thepresent applicant's co-pending international patent applications filedcontemporaneously with the present application, being patentapplications titled “Method and Apparatus for Locating the Surface ofSolid Growth Culture Media in a Plate”, “A Streaking ApplicatorCartridge and a System for Connecting Same to a Streaking Apparatus”,and “Method and Apparatus for Orientating a Solid Growth Culture MediumPlate”, the full contents of which are hereby incorporated by reference,for possibly fuller descriptions of some of these parts.

Illustrated in FIGS. 1 and 2 is an apparatus for inoculating andstreaking a solid growth culture medium in a plate. The apparatusincludes a plate supply (generally indicated by the letter A) thatincludes a plurality of input plate cassettes 10 (only cassettes 10 aand 10 f are shown) supported on an upper frame (not shown) for thesupply of raw plates to the apparatus, together with a plate store(generally indicated by the letter B) that includes a plurality ofoutput plate cassettes 11 (only cassettes 11 a and 11 f are shown) alsosupported on the upper frame for the storage of processed plates fromthe apparatus. Also shown in FIG. 1 is an inoculation and streakingstation, which is generally indicated by the letter C.

The plate supply A and the plate store B are supported by the upperframe so as to be in front of (in FIG. 1) a main gantry 12, along whichvarious of the operative carriages of the apparatus will move, as willbe explained below. The various parts of the inoculation and streakingstation C are generally supported by a lower frame, which is also notshown in FIG. 1 or 2.

Shown in FIG. 1 operatively engaged for sliding movement along the maingantry 12 is a plate supply carriage 14 a and a plate store carriage 14b, which form a part of a plate transfer feed mechanism and a platetransfer store mechanism (mentioned above) respectively. These carriagesare both configured for movement along the main gantry 12 (in the xdirection) to move a plate (16 a or 16 b) from the plate supply A to theinoculation and streaking station C and then to the plate store B. Thecarriages (14 a,14 b) are also configured to provide movement of a plate(16 a,16 b) along vertical guiderails (18 a,18 b) thereon to raiseand/or lower such plate (16 a,16 b) in the z direction to or from therespective cassettes (10 a to 10 f, and 11 a to 11 f) and to or fromeither or both of the dual plate orientation mechanisms (20 a, 20 b).

In this respect, it can be seen that each of the carriages includes aplate support tray (22 a,22 b) upon which the plates 16 a,16 b rest intransit, the plate support trays (22 a,22 b) being suitable mounted totheir respective carriages for the movement described above. It can alsobe seen that, in this embodiment of the invention, the plates aresupplied and stored in their respective cassettes in an invertedorientation, such that their bottoms are uppermost and their lids arelowermost.

Also configured for movement along the main gantry 12 are an inoculatingdevice 30 and a streaking device 40, in this embodiment again bothmounted upon a suitable carriage for movement along the main gantry inthe x direction. The inoculation device 30 is a pipette robot systemcontrolled so as to be able to access supply 32 of dispensing tips and asample supply system 34 that includes a number of supply tubes 36, andalso access a plate work position (one such position shown in FIG. 2 bythe letter D) for inoculation purposes. The streaking device 40 is astreaking robot system controlled so as to be able to access a streakingapplicator supply 42 that, in this embodiment, includes four applicatorsupply cartridges 46 received in four corresponding cartridge holders44.

Before turning to a more detailed description of some of these parts ofthis embodiment of the apparatus of the present invention, the lastgeneral aspect of FIGS. 1 and 2 to be described is the inoculation andstreaking station C. In this embodiment, the inoculation and streakingstation C of the apparatus includes dual plate work positions D and dualrotation devices (52 a,52 b) for the streaking of dual plates (beingindicated by reference numerals 16 c,16 d evident in FIG. 2 in the dualplate work positions D), and dual plate orientation mechanisms (20 a,20b), the location of which is all generally indicated in FIGS. 1 and 2 bythe reference numerals 50 a and 50 b. While FIG. 2 generally showsde-lidded plates 16 c,16 d in the plate work positions D underneath dualsensors (54 a,54 b), FIG. 1 shows dual plates (16 e,16 f) beingorientated and de-lidded by the dual orientation mechanisms (20 a,20 b).It will of course be appreciated that such a dual configuration is notessential for an apparatus in accordance with the present invention, andthat single such stations and devices could be used. Indeed, anapparatus that includes three or four or more such stations and devicesis also envisaged.

It can also be seen that, in this embodiment, the inoculating andstreaking station C is the general location within the apparatus wherethe main functions of the apparatus occur, which location is generallycentered around the plate work positions D. It can also be seen that, inthis embodiment, the plate work positions D are themselves identified by(and in essence defined by) the physical location in the apparatus ofthe sensors (54 a,54 b), the sensors (54 a,54 b) being rigidly mountedto respective sensor mounting frames (58 a,58 b). Therefore, theapparatus also includes dual plate platforms for supporting a plate,although the combination of FIGS. 1 and 2 shows four such platforms,being the dual platforms (60 a,60 b) in the positions shown in FIG. 1,and the platforms (62 a,62 b) shown in FIG. 2. In this respect, thesefigures each show two platforms (in different positions) simply for thesake of description—the apparatus of the embodiment will actually onlyinclude two such platforms.

Turning now to a more detailed description of some of the parts of theapparatus illustrated in FIGS. 1 and 2, reference is firstly made toFIGS. 3 a and 3 b that show examples of suitable removable cassettes (10a,11 a) for use in the plate supply A and the plate store B. Eachcassette (10 a,11 a) is able to hold multiple plates within their innerchambers (70 a,70 b)—in the case of cassette 10 a for the purpose ofproviding raw plates to the apparatus for subsequent processing, and inthe case of cassette 11 a for the purpose of storing processed platesfollowing inoculation and streaking in the apparatus. As can be seen,each of the cassettes (10 a,11 a) also interacts with its respectivecarriage (14 a,14 b) to capture a plate, from below, on the respectivetrays (22 a, 22 b) due to respective internal engaging and platerelease/lock means (not shown).

In relation to FIGS. 4 a and 4 b, as mentioned above, the inoculatingdevice 30 of the apparatus of the present invention can be any devicethat is able to obtain and hold a biological sample, generally in aliquid form, and transfer that sample to the surface of a medium in apositioned plate. In this embodiment, the inoculating device 30 ispipette device 31 mounted to a robot system (not shown) so as to bemovable in the z direction, as well as the x,y directions along the maingantry 12 as mentioned above.

The pipette device 31 includes a disposable dispensing tip 33 releasablysecured thereto in a manner that permits easy disposal of the tip 33once inoculation has been affected. The pipette device 31 isprogrammable for various inoculum volumes, and includes a positionalheight (z direction) referencing system (not shown) capable ofdetermining in three dimensional space the height of the location of thedispensing tip 33 relative to the datum level and reference points of aplatform (60 a,60 b,62 a,62 b) as will be described below, and of courserelative to the notional action line mentioned above.

The pipette robot system is able to move the pipette device 31 to accessa dispensing tip supply 32, which includes a rack 35 of dispensing tips33, the biological sample station 34, which includes a rack of samplecontainers such as sample tubes 36, the plate work position D in theinoculating and streaking station C, and also a tip waste disposal chute(not shown), whilst also including suitable tip securing means thatallows for a tip 33 to be secured, used to obtain and hold sample,dispense sample, and then dispose of the used tip 33.

Turning to FIG. 5, the streaking device 40 is a separate device to theinoculating device 30, and in this embodiment is provided by its ownrobot system that includes an applicator handling head 41 suitable toobtain (from a supply cartridge 46 in a cartridge holder 44) and hold astreaking applicator 45, and then transfer that applicator 45 to a platework position D and adjacent a positioned plate (generally all in thex,y plane). The applicator handling head 41 then must be able to movethe applicator 45 in the z direction to locate the line of contactsurfaces of the applicator 45 (here represented as being located alongthe lowermost curved portion 47 of the applicator 45, along the notionalaction line (and thus upon/within the inoculum on the surface of themedium in the positioned plate) as mentioned above and as will be betterdescribed below in relation to this embodiment.

As mentioned above, streaking applicators preferred for use with theapparatus of the present invention are the streaking applicatorsgenerally described in the abovementioned international patentpublication WO2005/071055 (Medvet Science Pty Ltd) titled “MicrobialStreaking Device” (licensed to the present applicant), the full contentof which is herein incorporated by reference. These streakingapplicators can be said to have a generally flat rectangular form,albeit with two major inclined portions that together form a veryshallow inverted v-shaped body. An upper portion 49 of the body providesa mounting portion and the lower curved portion 47 of the body providesthe line of spaced apart contact surfaces, there being a resilient andflexible support member therebetween, which in the form illustrated inFIG. 5 is made up of a plurality of elongate members.

The applicator handling head 41 of the streaking robot system thusincludes an openable clamping member 51 that is able to grasp and clampthe mounting portion 49 of the applicator 45 mentioned above, theapplicator 45 being provided in a supply cartridge 46 held in acartridge holder 44, both of the type generally described in the presentapplicant's concurrently filed international patent application referredto above and titled “A Streaking Applicator Cartridge and a System forConnecting Same to a Streaking Apparatus”.

The openable clamping member 51 of the streaking robot system preferablyincludes a release catch (not shown) which is able to interact with afixed eject pin (not shown) located near an applicator disposal chute(not shown), such that engagement of the pin with the latch causes theclamping member to release the applicator and allow it to fall into theapplicator disposal chute.

In relation to FIGS. 6 a and 6 b, the apparatus of this embodimentincludes dual orientation mechanisms (loosely identified in FIGS. 1 and2 by the reference numerals 50 a and 50 b) that are able to rotateplates (or at least plate bottoms) from a held position in an originalorientation to a worked orientation. FIGS. 6 a and 6 b show more detailof one of these mechanisms 50 a.

FIG. 6 a shows the mechanism 50 a commencing its operation to orientateand de-lid the plate 16 e for subsequent transfer of the plate bottom tothe plate work position D adjacent the sensor 54 a, while FIG. 6 b showsthe same plate 16 e orientated in the worked orientation, de-lidded, andtransferred such that the bottom of the plate 16 e is in the plate workposition D.

The plate 16 e has a lid 17 and a bottom 19 and, in this embodiment, isa circular plate that has a single perimetric sidewall 21. Theorientation mechanism 20 a includes opposed jaws (being a lower jaw 80and an upper jaw 82 when viewed in FIG. 6 a) able to receive and holdthe plate 16 e therebetween. One of the jaws (in this case the lower jaw80) is a retractable, vacuum-actuated lid-gripping device 84, the other(the upper jaw 82) is a retractable pair of elongate prongs spaced apartby a distance no larger than the diameter of the bottom 19 of the plate16 e, the upper jaw 82 also including a vacuum-actuated plate-bottomgripping device in the form of respective vacuum-actuated suction cups.

When initially placed between the jaws (80,82), the plate 16 e is heldtherebetween in a position that is thus defined as a “held position”.The held position defines a notional tube above and below the plate 16e, the notional tube being a continuation of a partial circular tubeformed by the sidewall 21 of the plate 16 e, which continuesindefinitely above and below the plate 16 e.

The orientation mechanism 20 a includes a jaw support member 86 uponwhich the upper jaw 82 is mounted. The upper jaw 82 is mounted on thesupport member 86 such that the plate 16 e rotates about a generallyhorizontal axis that intersects the notional tube to orientate the platebottom 19 from the original orientation to the worked orientation. Thejaw support member 86 is also movable generally vertically (in the ydirection) such that the plate bottom 19, during orientation, can thenbe lowered onto the plate platform 60 a from above (still within thenotional tube) such that the plate bottom 19 is moved downwardly in asmoothly continuous motion to engage with a plate clamping member 88,with the prongs of the jaw 82 being loosely received within acooperatively shaped channel 90 of the platform 60 a such that they arenot clamped when the plate 16 e is clamped.

In this embodiment, the plate clamping member 88 is in the form of threemovable lugs operated by a camming device (not shown), which lugs arepreferably also able to function as a plate centralizing means forcentralizing the position of the plate on the platform 60 a. This can beuseful for subsequent operations with the plate 16 e.

Then, in operation, and once the plate bottom 19 is clamped to andcentralized in the platform 88, the clamped bottom 19 can then be movedaway from the prongs horizontally (in the y direction), andindependently of the orientation mechanism 20 a, away from the notionaltube and into a plate work position D, where easy access to the mediumin the plate 16 e can be provided.

As will be appreciated, the reverse operation then moves the platform 60a, with the clamped bottom 19 of the plate 16 e (after processing in theplate work position D and with no lid 17), out of the plate workposition D within the notional tube of the held position, where theprongs are again loosely received within the channel 90 of the platform60 a by the plate clamping member 88 of the platform 60 a (and arearranged under the plate bottom 19). The lid 17 can then be re-appliedto the plate bottom 19 by slightly raising and then rotating the platebottom 19 back up and around the lid 17 to be returned to its originalorientation.

The orientation mechanism 50 a is more fully described in the presentapplicant's concurrently filed international patent application referredto above and titled “Method and Apparatus for Orientating a Solid GrowthCulture Medium Plate”.

Finally with reference to FIGS. 7 a and 7 b, reference can be made tooperations that occur in the plate work position D identified earlier inFIGS. 1 and 2. With reference to FIG. 7 a, illustrated is a plateplatform 60 a with a plate bottom 19 in a centralized and clampedposition in the plate work position D. As mentioned above, the plateplatform 60 a includes a plate clamping member 32 in the form of threemovable lugs operated by a camming device (not shown), which lugs arepreferably also able to function as a plate centralizing means forcentralizing the position of the plate bottom 19 on the platform 60 a.

The plate work position D includes a notional action line X (shown by abroken line in FIG. 6 a) fixed in two dimensions (x,y) in apredetermined position, together with a datum level Y, which in FIG. 6 ais shown as a surface upon the plate platform 60 a (eventually to belocated within the plate work position D as per the illustration in FIG.7 a). In the present invention, the notional action line X is fixed intwo dimensions (x,y) in a predetermined position. Again as mentionedabove, the action line is herein referred to as being a “notional”action line given that it will not be a visible action line and alsowill not have a determined position in three dimensional space until theheight of the surface 100 of the medium in the plate bottom 19 isdetermined.

FIG. 7 a shows an apparatus for locating the surface 100 in the platebottom 19, and includes the sensor 54 a. In this embodiment of theinvention, the notional action line X is of course fixed in twodimensions (x,y) in its predetermined position, and the plate workposition D includes a datum level Y, which is the uppermost surface uponthe plate platform 60 a.

The sensor 54 a includes an ultrasonic sensing device 55 a having anultrasonic beam focusing element that is capable of providing a focusedbeam on the surface 100, preferably within a sensing region (notidentified in FIG. 7 a) that is central to the notional action line X.The sensor 54 a is rigidly mounted via a sensor support arm 58 a,thereby defining the general location of the plate work position D. Inthis form, the sensor 54 a is ideally mounted so that it is above theplate work position D and is operatively adjacent the plate bottom 19held immediately therebelow in the plate platform 60 a, the plate bottom19 having its surface 100 open upwardly.

The preferred operation of the sensor is thus for it to sense thesurface 100 and measure the distance to the surface 100. Then, themeasured distance is referenced to the datum level Y to determine asurface positional reference relative to the datum level Y in onedimension (z) for the surface 100 in the plate bottom 19. In thismanner, it will be appreciated that the surface 100 can thus be locatedin at least the z dimension by virtue of the determination of thissurface positional reference. This effectively determines the height ofthe medium in the plate bottom 19, at least with reference to that datumlevel Y. In this respect, and as can be seen in the figures, the datumlevel Y is a surface that forms a part of the plate platform 60 a uponwhich the plate is clamped and supported. Therefore, in this embodiment,the determination of the surface positional reference effectivelydetermines the height of the medium with reference to the plate platform60 a upon which it rests.

This surface positional reference can then be used, together with thenotional action line X (shown in earlier figures) to determine the lineG in three dimensions (x,y,z) that is representative of a line acrossthe surface 100 in the positioned plate.

As with other parts of the apparatus of the present invention, thesensor 54 a is more fully described in the present applicant'sconcurrently filed international patent application referred to aboveand titled “Method and Apparatus for Locating the Surface of SolidGrowth Culture Media in a Plate”.

The notional three dimensional action line that is represented by theline G across the surface 100 of the medium in the plate bottom 19 willbe specific to the medium in that plate bottom 19 only, and may be (andis actually likely to be) a different three dimensional action linecompared to the surface of the next plate processed in the plate workposition D. In the preferred form illustrated here, the predetermined(x,y) position of the notional action line X is, with reference to thecircular plate bottom 19, located such that the notional action line Xwill be a radial line for a circular plate, which then means that theline G which represents the action line in three dimensions (x,y,z) willbe also.

In this form, and as shown in FIG. 7 a, having utilized the sensor todetermine the proper position of the three dimensional action line,represented by the line G in FIG. 7 a, for media in a given positionedplate in three dimensional space, during inoculation of the surface 100of the medium in the apparatus of the present invention by theinoculating device 30, the biological sample can be deposited on thesurface 100 of the medium along the radial line G in a manner such thatthe dispensing tip 33 is not located too far away from the surface 100nor too close to the surface 100. In this respect, it will beappreciated that a reference throughout this specification to abiological sample being dispensed “along” a line (or there beinginoculation “along” a line), is to include a variety of forms ofdepositing/inoculation. For example, a sample may be depositedcontinuously along the full length of the line, or may be depositedsemi-continuously along the line, such as may be provided by a series ofdiscrete deposits in the form of dots and/or dashes as required.

Now referring to FIG. 7 b, the apparatus of the present invention isthen able to move the streaking device 40 such that the line of spacedapart contact surfaces of a streaking applicator 45 contacts, againalong that line G, at least the inoculum (and preferably also thesurface 100 of the medium itself) on the surface 100 of the medium inthe plate bottom 19, with a predetermined contact pressure that issuitable for the particular streaking applicator 45 being used and alsofor the composition of the inoculum and of the particular solid growthmedium being used, such that the inoculum is spread when the platform 60a is rotated in the direction of arrow H, such that the streakingapplicator 45 does not undesirably gouge the surface of the medium.

Certain embodiments or configurations of the present invention may bedescribed by the following aspects:

-   1. An apparatus for inoculating and streaking a medium in a plate,    the streaking using a streaking applicator having a line of    resiliently and flexibly supported spaced apart contact surfaces,    the apparatus including:    -   (a) an inoculating and streaking station including:        -   a plate work position having a notional action line fixed in            two dimensions (x,y) in a predetermined position; and        -   a plate rotation device for rotating a positioned plate to            cause streaking;    -   (b) a sensor capable of locating the surface of the medium in a        positioned plate to thereby determine for that plate, prior to        inoculation and streaking, the third dimension (z) of the action        line;    -   (c) an inoculating device capable of dispensing inoculum, along        the action line, on the surface of the medium in the positioned        plate; and    -   (d) a streaking device capable of moving the streaking        applicator such that its line of spaced apart contact surfaces        contacts, along the action line, the surface of the medium in        the positioned plate, prior to rotation of the positioned plate        for streaking.-   2. An apparatus according to aspect 1, including a platform for    supporting a plate, the platform able to be moved into and out of    the plate work position from a plate loading position, such that the    plate supported in the platform becomes positioned in the plate work    position operatively adjacent the sensor.-   3. An apparatus according to aspect 2, wherein the platform includes    a plate centering mechanism for constant central positioning of a    plate upon the platform.-   4. An apparatus according to aspect 3, wherein the plate centering    mechanism includes a plate clamping function.-   5. An apparatus according to any one of aspects 2 to 4, wherein the    platform provides a datum level.-   6. An apparatus according to any one of aspects 2 to 5, wherein the    plate rotation device is provided in association with the platform,    the rotation device including a home flag which allows for the    return of a rotated plate to a starting position.-   7. An apparatus according to any one of aspects 1 to 6, wherein the    plate work position is provided by the physical location in the    apparatus of the sensor, the sensor being rigidly mounted to a main    frame.-   8. An apparatus according to any one of aspects 1 to 7, wherein the    sensor is an ultrasonic sensing device having an ultrasonic beam    focusing element to provide a focused beam on the surface of the    medium.-   9. An apparatus according to aspect 8, wherein the beam is focused    within a usable area that is central to the action line in its    predetermined (x,y) position.-   10. An apparatus according to aspect 8 or aspect 9, when appended    via claim 5, wherein the sensor senses the surface and measures the    distance to the surface, then referencing the measured distance to    the datum level to determine a surface positional reference relative    to the datum level in one dimension (z) for the surface, and uses    the surface positional reference and the two fixed dimensions of the    notional action line to determine the notional action line in three    dimensions (x,y,z).-   11. An apparatus according to any one of aspects 1 to 10, wherein    the inoculating device includes a pipette device mounted to a robot    system so as to be movable in the z direction and at least one of    the x,y directions.-   12. An apparatus according to aspect 11, wherein the pipette device    includes a disposable tip releasably secured to a pipette body.-   13. An apparatus according to aspect 11 or aspect 12, when appended    via claim 5, wherein the pipette device is programmable for various    inoculum volumes, and includes a positional height (z direction)    referencing system relative to the locating datum surface of the    platform.-   14. An apparatus according to any one of aspects 1 to 13, wherein    the streaking device includes a robot system that includes an    applicator handling head suitable to obtain and hold a streaking    applicator, and then transfer that applicator to the plate work    position adjacent a positioned plate.-   15. An apparatus according to aspect 14, wherein the applicator    handling head is able to move the applicator in the z direction to    locate the line of contact surfaces of the applicator along the    notional action line on the surface of the medium in a positioned    plate.-   16. An apparatus according to aspect 14 or aspect 15, wherein the    applicator handling head of the streaking robot system includes an    openable clamping member that is able to grasp and clamp a mounting    portion of a streaking applicator.-   17. An apparatus according to aspect 16, wherein the openable    clamping member of the streaking robot system includes a release    catch which is able to interact with a fixed eject pin located near    an applicator disposal chute, such that engagement of the pin with    the latch causes the clamping member to release the applicator and    allow it to fall into the applicator disposal chute.-   18. An apparatus according to aspect 1 substantially as herein    described in relation to the accompanying Figures.-   19. A method for inoculating and streaking a medium in a plate, the    streaking using a streaking applicator having a line of resiliently    and flexibly supported spaced apart contact surfaces, the method    including the steps of:    -   (a) placing a plate in a plate work position in an inoculating        and streaking station, the plate work position having a notional        action line fixed in two dimensions (x,y) in a predetermined        position;    -   (b) locating the surface of the medium in the positioned plate        to thereby determine for that plate, prior to inoculation and        streaking of that plate, the third dimension (z) of the action        line;    -   (c) dispensing inoculum along the action line on the surface of        the medium in the positioned plate;    -   (d) moving the streaking applicator such that its line of spaced        apart contact surfaces contacts, along the action line, the        surface of the medium in the positioned plate; and    -   (e) rotating the positioned plate in the plate work position for        streaking-   20. A method according to aspect 19, wherein the plate work position    also has a datum level.-   21. A method according to aspect 20, the method including the use of    a sensor to sense the surface and measure the distance to the    surface, referencing the measured distance to the datum level to    determine a surface positional reference relative to the datum level    in one dimension (z) for the surface.-   22. A method according to aspect 21, including using the surface    positional reference and the two fixed dimensions of the notional    action line to determine the notional action line in three    dimensions (x,y,z), the notional action line being a line    representative of the surface of the medium.-   23. A method according to aspect 22, including dispensing inoculum    along the representative line across the surface of the medium in    the positioned plate.-   24. A method according to aspect 19, substantially as herein    described in relation to the accompanying Figures.-   25. An apparatus for inoculating and streaking a solid growth    culture medium in a plate, the streaking using a streaking    applicator having a line of resiliently and flexibly supported    spaced apart contact surfaces, the apparatus including:    -   (a) a plate supply capable of storing raw plates in an inverted        orientation;    -   (b) a plate transfer feed mechanism capable of obtaining an        inverted raw plate from the plate supply, orientating the raw        plate such that its bottom is lowermost and its lid is removed,        and transferring the orientated and de-lidded raw plate to the        plate work position in an inoculating and streaking station;    -   (c) the inoculating and streaking station including:        -   the plate work position, having a notional action line fixed            in two dimensions (x,y) in a predetermined position; and        -   a plate rotation device for rotating a positioned plate to            cause streaking;    -   (d) a sensor capable of locating the surface height of the        medium in a positioned plate to thereby determine for that        plate, prior to inoculation and streaking of that plate, the        third dimension (z) of the action line;    -   (e) an inoculating device capable of dispensing inoculum, along        the action line, on the surface of the medium in the positioned        plate;    -   (f) a streaking device capable of moving the streaking        applicator such that its line of spaced apart contact surfaces        contacts, along the action line, the surface of the medium in        the positioned plate, prior to rotation of the positioned plate        for streaking;    -   (g) a plate store capable of storing processed plates in an        inverted orientation; and    -   (h) a plate transfer store mechanism capable of retrieving a        processed plate from the plate work position, re-orientating the        processed plate to its inverted orientation with its lid on, and        transferring the processed plate to the plate store.-   26. An apparatus according to aspect 25, wherein the plate supply is    formed by a plurality of removable cassettes, each cassette able to    hold and then feed multiple raw plates to the plate transfer    mechanism.-   27. An apparatus according to aspect 25 or aspect 26, wherein the    plate transfer feed mechanism includes an orientation mechanism, the    orientation mechanism providing for orientation of at least the raw    plate bottom about a generally horizontal axis, before the de-lidded    raw plate is transferred into the plate work position.-   28. An apparatus according to aspect 27, wherein the orientation    mechanism is provided by a pair of opposed plate receiving jaws.-   29. An apparatus according to aspect 28, wherein at least one of the    jaws is provided by a retractable, vacuum-actuated device, and one    is provided by a pair of elongate prongs.-   30. An apparatus according to aspect 29, wherein at least one of the    jaws is mounted for rotation about an axis in one of the x or y    directions such that the inverted raw plate held between the jaws    can have at least its bottom orientated by 180 degrees about that    axis to bring the plate bottom into its upright orientation.-   31. An apparatus according to aspect 30, wherein the orientation    mechanism is then able to move to be located over a platform,    following which the upright and held raw plate bottom may be lowered    onto the platform.-   32. An apparatus according to aspect 31, wherein the raw plate is    left centralized and clamped upon the platform ready to be moved    into the plate work position.-   33. An apparatus according to any one of aspects 25 to 32, wherein    the plate store is formed by a plurality of removable cassettes,    each cassette able to receive multiple processed plates from the    plate transfer store mechanism and then store multiple processed    plates.-   34. An apparatus according to any one of aspects 27 to 32, wherein    the orientation mechanism forms a part of the plate transfer store    mechanism, and functions to retrieve the processed plate bottom from    the plate work position, and re-orientate the processed plate bottom    to its original inverted orientation with its lid on.-   35. An apparatus according to aspect 25, substantially as herein    described in relation to the accompanying Figures.-   36. A method for inoculating and streaking a solid growth culture    medium in a plate, the streaking using a streaking applicator having    a line of resiliently and flexibly supported spaced apart contact    surfaces, the method including the steps of:    -   (a) storing raw plates in an inverted orientation in a plate        supply;    -   (b) obtaining an inverted raw plate from the plate supply,        orientating the raw plate such that its bottom is lowermost and        its lid is off, and transferring the orientated and de-lidded        raw plate to a plate work position in an inoculating and        streaking station, the plate work position having a notional        action line fixed in two dimensions (x,y) in a predetermined        position;    -   (c) locating the surface of the medium in the positioned plate        to thereby determine for that plate, prior to inoculation and        streaking of that plate, the third dimension (z) of the action        line;    -   (d) dispensing inoculum along the action line on the surface of        the medium in the positioned plate;    -   (e) moving the streaking applicator such that its line of spaced        apart contact surfaces contacts, along the action line, the        surface of the medium in the positioned plate;    -   (f) rotating the positioned plate in the plate work position for        streaking; and    -   (g) retrieving the processed plate from the plate work position,        re-orientating the processed plate to its inverted orientation        with its lid on, and transferring the processed plate to a plate        store.-   37. A method according to aspect 34 substantially as herein    described in relation to the accompanying Figures.-   38. A plate that has been inoculated and streaked by an apparatus    according to any one of aspects 1 to 18.-   39. A plate that has been inoculated and streaked by an apparatus    according to any one of aspects 25 to 35-   40. A plate that has been inoculated and streaked by a method    according to any one of aspects 19 to 24.-   41. A plate that has been inoculated and streaked by a method    according to aspect 36 or aspect 37.

In conclusion, it must be appreciated that there may be other variationsand modifications to the configurations described herein which are alsowithin the scope of the present invention.

We claim:
 1. An apparatus for automatically inoculating and streaking amedium in a plate, the streaking using a streaking applicator having aline of resiliently and flexibly supported spaced apart contactsurfaces, the apparatus including: (a) an inoculating and streakingstation including: a predetermined plate work position having a notionalaction line fixed in two dimensions (x, y); and a plate rotation device;(b) a sensor arranged to locate the surface of the medium in a platepositioned in the plate work position to thereby determine for thatplate, prior to inoculation and streaking, a third dimension (z) of theaction line determined by the surface of the medium in that plate; (c)an inoculating device arranged to dispense inoculum, along the actionline as determined by the two fixed dimensions (x, y) and the thirddimension (z) of the plate located in the plate work position asdetermined by the sensor; and (d) a streaking device capable of movingthe streaking applicator such that its line of spaced apart contactsurfaces contacts at least the inoculum dispensed along the action lineof the plate located in the plate work position, prior to rotation ofthe plate by the plate rotation device.
 2. An apparatus according toclaim 1, including a platform for supporting a plate, the platform ableto be moved into and out of the plate work position from a plate loadingposition, such that the plate supported in the platform becomespositioned in the plate work position operatively adjacent the sensor.3. An apparatus according to claim 2, wherein the platform includes aplate centering mechanism for constant central positioning of a plateupon the platform.
 4. An apparatus according to claim 3, wherein theplate centering mechanism includes a plate clamping function.
 5. Anapparatus according to claim 2, wherein the platform provides a datumlevel.
 6. An apparatus according to claim 2, wherein the plate rotationdevice is provided in association with the platform, the rotation deviceincluding a home flag which allows for the return of a rotated plate toa starting position.
 7. An apparatus according to claim 1, wherein theplate work position is provided by the physical location in theapparatus of the sensor, the sensor being rigidly mounted to a mainframe.
 8. An apparatus according to claim 1, wherein the sensor is anultrasonic sensing device having an ultrasonic beam focusing element toprovide a focused beam on the surface of the medium of the plate in thepredetermined plate work position.
 9. An apparatus according to claim 8,wherein the beam is focused within a usable area that is central to theaction line in its predetermined (x, y) position.
 10. An apparatusaccording to claim 8, including a platform for supporting a plate, theplatform able to be moved into and out of the plate work position from aplate loading position, such that the plate supported in the platformbecomes positioned in the plate work position operatively adjacent thesensor, wherein the platform provides a datum level, and wherein thesensor senses the surface and measures the distance to the surface, thenreferencing the measured distance to the datum level to determine asurface positional reference relative to the datum level in onedimension (z) for the surface, and uses the surface positional referenceand the two fixed dimensions of the notional action line to determinethe notional action line in three dimensions (x, y, z).
 11. An apparatusaccording to claim 1, wherein the inoculating device includes a pipettedevice mounted to a robot system so as to be movable in the z directionand at least one of the x, y directions.
 12. An apparatus according toclaim 11, wherein the pipette device includes a disposable tipreleasably secured to a pipette body.
 13. An apparatus according toclaim 11, including a platform for supporting a plate, the platform ableto be moved into and out of the plate work position from a plate loadingposition, such that the plate supported in the platform becomespositioned in the plate work position operatively adjacent the sensor,wherein the platform provides a datum level, and wherein the pipettedevice is programmable for various inoculum volumes, and includes apositional height (z direction) referencing system relative to thelocating datum surface of the platform.
 14. An apparatus according toclaim 1, wherein the streaking device includes a robot system thatincludes an applicator handling head suitable to obtain and hold astreaking applicator, and then transfer that applicator to the platework position adjacent a positioned plate.
 15. An apparatus according toclaim 14, wherein the applicator handling head is able to move theapplicator in the z direction to locate the line of contact surfaces ofthe applicator along the notional action line on the surface of themedium in a positioned plate.
 16. An apparatus according to claim 14,wherein the applicator handling head of the streaking robot systemincludes an openable clamping member that is able to grasp and clamp amounting portion of a streaking applicator.
 17. An apparatus accordingto claim 16, wherein the openable clamping member of the streaking robotsystem includes a release catch which is able to interact with a fixedeject pin located near an applicator disposal chute, such thatengagement of the pin with the latch causes the clamping member torelease the applicator and allow it to fall into the applicator disposalchute.
 18. A plate that has been inoculated and streaked by an apparatusaccording to claim 1.